Regeneratable system for contaminant removal

Abstract

A system and method for water purification by capture of contaminants in an aqueous mixture is described herein. A system and method for regenerating the capture system is also described. An integrated capture and regeneration system and method is also described including a separation vessel that houses a capture bed and optionally an electrode in electrical contact with the bed with a power source for applying a voltage to the electrode. The applied voltage enhances capture of the contaminant from aqueous liquid on the capture bed and modulation of the applied voltage enhances release of contaminant on the capture bed into aqueous wash liquid to regenerate the bed. The aqueous wash liquid may contain a counter ion that binds to the contaminant forming an aggregate contaminant phase that separates from the aqueous wash liquid.

What is claimed is: 
     
         1 . A method of removing a contaminant from an aqueous mixture comprising flowing a contaminated aqueous mixture comprising one or more ionic contaminants through a vessel that houses a capture bed, and flowing an aqueous wash liquid through the vessel. 
     
     
         2 . The method of  claim 1 , further comprising applying a voltage to an electrode that is in electrical contact with the capture bed, such that the one or more ionic contaminants is bound to the capture bed, and modulating the voltage applied to the electrode, such that the one or more ionic contaminants bound to the capture bed is released from the capture bed and is washed from the capture bed via the aqueous wash liquid. 
     
     
         3 . The method of  claim 1  or  2 , wherein the aqueous wash liquid comprises a counter ion that binds to the ionic contaminant forming an aggregate contaminant phase, and wherein the method further comprises removing the aggregate contaminant phase from the aqueous wash liquid. 
     
     
         4 . The method of  claim 3 , wherein the counter ion is a cation selected from Ca 2+ , Mg 2+ , Zn 2+ , Sr 2+ , Al 3+ , B 3+ , or Fe 3+ ; or wherein the counter ion is an anion selected from a phosphate, a sulfate, or a borate. 
     
     
         5 . The method of  claim 3  or  4 , wherein the aggregate contaminant phase separates from the aqueous wash liquid by precipitation. 
     
     
         6 . The method of  claim 1  or  2 , further comprising contacting the released ionic contaminant in the aqueous wash liquid with a stationary ion source, such that the ionic contaminant is bound to the stationary ion source and is thereby removed from the aqueous wash liquid. 
     
     
         7 . The method of any one of  claims 2  to  6 , wherein applying the voltage to the electrode comprises running an electrical current to the electrode, and modulating the voltage comprises reducing or reversing the electrical current running to the electrode. 
     
     
         8 . The method of any one of  claims 1  to  7 , wherein the contaminated aqueous mixture is flowed into the vessel at a rate from about 5 to about 400 liters per minute per square meter of capture bed. 
     
     
         9 . The method of any one of  claims 2  to  8 , wherein the voltage used to bind contaminants to the capture bed has a positive polarity from about 0.01 V to about 1.6 V. 
     
     
         10 . The method of any one of  claims 1  to  9 , wherein the pressure drop across the capture bed is from about 1 psi to about 200 psi. 
     
     
         11 . The method of any one of  claims 1  to  10 , wherein the aqueous wash liquid is flowed into the vessel at a rate of from about 5 to about 400 liters per minute per square meter of capture bed. 
     
     
         12 . The method of any one of  claims 7  to  11 , wherein modulating the voltage to release the ionic contaminant comprises reducing the electric current to generate a modulated voltage having a positive polarity of from about 0.01 V to about 1.5 V. 
     
     
         13 . The method of any one of  claims 7  to  11 , wherein modulating the voltage to release the ionic contaminant comprises reversing the electric current to generate a modulated voltage having a negative polarity of from about −0.01 V to about −1.6 V. 
     
     
         14 . The method of one of  claims 7  to  11 , wherein modulating the voltage to release the ionic contaminant comprises applying an AC voltage optionally with a DC offset. 
     
     
         15 . The method of any one of  claims 1  to  14 , wherein the aqueous wash liquid is at least substantially saturated with the ionic contaminant upon exiting the capture bed. 
     
     
         16 . The method of any one of  claims 1  to  15 , further comprising binding an ionic complexing species to the capture bed prior to flowing the contaminated aqueous mixture through the vessel, such that upon flowing the contaminated aqueous mixture through the vessel, the ionic contaminant binds to the capture bed by forming a complex with the ionic complexing species wherein the complex is bound to the capture bed. 
     
     
         17 . The method of  claim 16 , wherein the ionic complexing species is Ca′, Mg′, Al′, phosphate, or borate. 
     
     
         18 . The method of any one of  claims 1  to  17 , wherein the capture bed is situated in the vessel such that the contaminated aqueous mixture flows by or through the capture bed. 
     
     
         19 . The method of any one of  claims 1  to  18 , wherein the capture bed is adjacent to a separator. 
     
     
         20 . The method of  claim 19 , wherein the capture bed is wrapped in a separator, enclosed within a separator, or sandwiched between two separators. 
     
     
         21 . The method of any one of  claims 1  to  20 , further comprising flowing the contaminated aqueous mixture through a second vessel that houses a second capture bed. 
     
     
         22 . The method of  claim 21 , wherein the second capture bed is in electrical contact with a second electrode, the method further comprising applying a voltage to the second electrode that is in electrical contact with the second capture bed. 
     
     
         23 . The method of any one of  claims 1  to  20 , wherein the vessel further houses a second capture bed. 
     
     
         24 . The method of  claim 23 , wherein the second capture bed is in electrical contact with a second electrode, the method further comprising applying a voltage to the second electrode that is in electrical contact with the second capture bed. 
     
     
         25 . The method of  claim 24 , wherein the second capture bed is adjacent to the first capture bed with a separator disposed between the first and second capture beds. 
     
     
         26 . The method of  claim 24  or  25 , wherein a positive voltage is applied to one of the first and second capture beds, and a negative voltage is applied to the other of the first and second capture beds. 
     
     
         27 . The method of any one of  claims 23  to  26 , wherein the vessel comprises a capture bed stack comprising a plurality of capture beds. 
     
     
         28 . The method of  claim 27 , wherein the plurality of capture beds are separated from each other by one or more separators. 
     
     
         29 . The method of  claim 28 , wherein the plurality of capture beds are in electrical contact with the first or second electrode. 
     
     
         30 . The method of  claim 29 , comprising applying a positive voltage to the first electrode, wherein the first electrode is in electrical contact with a first plurality of capture beds; and applying a negative voltage to the second electrode, wherein the second electrode is in electrical contact with a second plurality of capture beds. 
     
     
         31 . The method of  claim 30 , wherein the first plurality of capture beds are stacked in an alternating fashion with the second plurality of capture beds. 
     
     
         32 . The method of any one of  claims 1  to  31 , wherein the ionic contaminant comprises an organic end with an ionic moiety. 
     
     
         33 . The method of any one of  claims 1  to  31 , wherein the ionic contaminant is selected from the group consisting of a polyfluoroalkyl ion, a borate, a phosphate, a polyphosphate, a sulfate, an organic acid, a fatty acid, a humic substance, a shortchain PFAS, a water-soluble medication, a detergent, a water-soluble insecticide, a water-soluble fungicide, a water-soluble germicide, and any combination thereof. 
     
     
         34 . The method of  claim 33 , wherein the ionic contaminant is a polyfluoroalkyl ion. 
     
     
         35 . The method of  claim 34 , wherein the polyfluoroalkyl ion is perfluorooctanesulfonate or perfluorooctanoate. 
     
     
         36 . The method of any one of  claims 1  to  35 , wherein the capture bed is at least partially conductive. 
     
     
         37 . The method of  claim 36 , wherein the capture bed is an activated carbon bed. 
     
     
         38 . The method of  claim 36 , wherein the capture bed is an ion exchange resin bed. 
     
     
         39 . The method of any one of  claims 1  to  36 , wherein the capture bed comprises powder, granules, beads, pellets, cloths, felts, nonwoven fabrics, or composites comprising a material selected from carbon, nitrogen-doped carbon, boron-doped carbon, charcoal, graphite, biochar, coke, carbon black, or any combination thereof. 
     
     
         40 . The method of  claim 39 , wherein the capture bed comprises activated charcoal powder, granules, pellets, beads, or any combination thereof. 
     
     
         41 . The method of any one of  claims 1  to  37 , wherein the capture bed comprises activated carbon having an average surface area of from about 100 m 2 /g to about 2000 m 2 /g. 
     
     
         42 . The method of any one of  claims 1  to  41 , wherein the capture bed has a conductivity of from about 0.01 S/cm to about 100 S/cm. 
     
     
         43 . The method of any one of  claims 1  to  42 , wherein the capture bed is surface-modified with functional groups selected from the group consisting of an acid, a hydroxide, a chloride, a bromide, a fluoride, an ether, an epoxide, a quinone, a ketone, an aldehyde, a pyrrole, a thiophene, and any combination thereof. 
     
     
         44 . The method of any one of  claims 1  to  43 , wherein the capture bed has a porosity of from about 30% to about 95%. 
     
     
         45 . The method of any one of  claims 1  to  44 , wherein the capture bed further comprises a binder dispersed in the capture bed. 
     
     
         46 . The method of  claim 45 , wherein the binder comprises a wax, a starch, a sugar, a polysaccharide, or any combination thereof. 
     
     
         47 . The method of any one of  claims 19  to  46 , wherein the separator comprises a porous plastic. 
     
     
         48 . The method of any one of  claims 1  to  47 , wherein the vessel is a pipe, column, or tank. 
     
     
         49 . The method of any one of  claims 1  to  48 , wherein the electrode comprises graphite, titanium, stainless steel, cast iron, a conductive metal oxide, a conductive diamond, a titanium suboxide, titanium nitride, titanium carbide, titanium boride, a doped manganese oxide, or mixtures or composites thereof. 
     
     
         50 . The method of any one of  claims 1  to  49 , wherein the aqueous wash liquid comprises untreated contaminated aqueous mixture. 
     
     
         51 . The method of any one of  claims 1  to  50 , wherein the aqueous wash liquid comprises a C 1-5  alcohol. 
     
     
         52 . The method of any one of  claims 1  to  51 , wherein the aqueous wash liquid further comprises an antifreeze agent that lowers the freezing point of the aqueous wash liquid. 
     
     
         53 . The method of  claim 52 , wherein the antifreeze agent is selected from the group consisting of propylene glycol, polypropylene glycol, polyethylene glycol, glycerol, polyvinyl alcohol, carboxymethylcellulose, ribose, sucrose, glucose, rhamnose, xylose, fructose, raffinose, stachyose, low molecular weight hydroxyethyl starches, maltodextrin, cellodextrins and any mixture thereof. 
     
     
         54 . The method of  claim 52  or  53 , wherein the aqueous wash liquid comprises from about 0.1 wt % to about 20 wt % of the antifreeze agent. 
     
     
         55 . The method of any one of  claims 52  to  54 , wherein the freezing point of the aqueous wash liquid is below about −0.3° C. 
     
     
         56 . The method of any one of  claims 1  to  55 , wherein the aqueous wash liquid further comprises one or more additives selected from the group consisting of acetic acid, propanoic acid, octanoic acid, glycolic acid, citric acid, ethylenediaminetetraacetic acid (EDTA), a water-soluble fatty acid, a salt of the aforementioned acids, and any mixture thereof. 
     
     
         57 . The method of  claim 56 , wherein the concentration of the one or more additives in the aqueous wash liquid is from about 0.1 wt % to about 15 wt % by weight of the aqueous wash liquid. 
     
     
         58 . The method of any one of  claims 1  to  57 , further comprising flowing an aqueous rinse liquid through the vessel, wherein the rinse liquid comprises one or more additives selected from the group consisting of acetic acid, propanoic acid, octanoic acid, glycolic acid, citric acid, ethylenediaminetetraacetic acid (EDTA), a water-soluble fatty acid, a salt of the aforementioned acids, and any mixture thereof. 
     
     
         59 . The method of  claim 58 , wherein the concentration of the one or more additives in the rinse liquid is from about 0.1 wt % to about 15 wt % by weight of the rinse liquid. 
     
     
         60 . A system for removing a contaminant from water comprising:
 a separation vessel and disposed therein a capture bed;   an intake line fluidly coupled to the vessel and configured to introduce a flow of a contaminated aqueous mixture to the vessel such that one or more ionic contaminants in the contaminated aqueous mixture binds to the capture bed; and   a regeneration line fluidly coupled to the vessel and configured to introduce a flow of aqueous wash liquid to the vessel to wash ionic contaminant from the capture bed.   
     
     
         61 . The system of  claim 60 , further comprising:
 an electrode in electrical contact with the capture bed;   a power source electrically coupled to, and configured to apply a voltage to, the electrode that is in electrical contact with the capture bed; and   a controller configured to control and modulate the voltage applied from the power source to the electrode.   
     
     
         62 . The system of  claim 60  or  61 , wherein the aqueous wash liquid comprises a counter ion that binds to the one or more ionic contaminants thereby forming an aggregate contaminant phase that is substantially insoluble in the aqueous wash liquid. 
     
     
         63 . The system of  claim 62 , wherein the counter ion is a cation selected from Ca 2+ , Mg 2+ , Zn 2+ , Sr 2+ , Al 3+ , B 3+ , or Fe 3+ ; or wherein the counter ion is an anion selected from a phosphate, a sulfate, or a borate. 
     
     
         64 . The system of  claim 62  or  63 , further comprising a filter configured to remove the aggregate contaminant phase from the aqueous wash liquid. 
     
     
         65 . The system of  claim 60  or  61 , further comprising a regeneration vessel that houses a stationary ion source configured to bind the one or more ionic contaminants in the aqueous wash liquid, wherein the regeneration vessel is fluidly coupled to the separation vessel. 
     
     
         66 . The system of any one of  claims 61  to  65 , wherein the controller is configured to reduce or reverse the current applied from the power source. 
     
     
         67 . The system of any one of  claims 60  to  66 , further comprising a pump fluidly coupled to the intake line and configured to pump the contaminated aqueous mixture into the vessel at a flow rate of from about 5 to about 400 liters per minute per square meter of capture bed. 
     
     
         68 . The system of any one of  claims 61  to  67 , wherein the power source is configured to apply a voltage to the electrode, wherein the voltage is from about ±0.01 V to about ±1.6 V. 
     
     
         69 . The system of any one of  claims 60  to  68 , further comprising a regeneration pump fluidly coupled to the regeneration line and configured to pump aqueous wash liquid into the separation vessel at a flow rate of from about 5 to about 400 liters per minute per square meter of capture bed. 
     
     
         70 . The system of any one of  claims 61  to  69 , wherein the controller is further configured to reduce the voltage applied to the electrode, reverse the polarity of the voltage applied to the electrode, terminate the voltage applied to the electrode, or any combination thereof. 
     
     
         71 . The system of any one of  claims 60  to  70 , further comprising an ionic complexing species bound to the capture bed. 
     
     
         72 . The system of  claim 71 , wherein the ionic complexing species is Ca′, Mg′, Al′, phosphate, or borate. 
     
     
         73 . The system of any one of  claims 60  to  72 , wherein the capture bed is disposed longitudinally along the flow axis of the separation vessel such that the contaminated aqueous mixture flows by the capture bed. 
     
     
         74 . The system of any one of  claims 60  to  72 , wherein the capture bed is disposed laterally across the separation vessel such that the water flows through the capture bed. 
     
     
         75 . The system of any one of  claims 60  to  72 , wherein the capture bed is adjacent to a separator. 
     
     
         76 . The system of  claim 75 , wherein the capture bed is wrapped in a separator, enclosed within a separator, or sandwiched between two separators. 
     
     
         77 . The system of any one of  claims 60  to  76 , further comprising a second separation vessel that houses a second capture bed. 
     
     
         78 . The system of  claim 77 , further comprising a second electrode in electrical contact with the second capture bed. 
     
     
         79 . The system of  claim 78 , wherein the power source or a second power source is configured to apply a voltage to the second electrode that is in electrical contact with the second capture bed. 
     
     
         80 . The system of any one of  claims 60  to  76 , wherein the vessel further houses a second capture bed. 
     
     
         81 . The system of  claim 80 , further comprising a second electrode in electrical contact with the second capture bed. 
     
     
         82 . The system of  claim 81 , wherein the second capture bed is adjacent to the first capture bed with a separator disposed between the first and second capture beds. 
     
     
         83 . The system of  claim 82 , wherein the separator is disposed around the first and second capture beds in a Z-fold, S-fold, or C-fold arrangement. 
     
     
         84 . The system of any one of  claims 81  to  83 , wherein the power source is configured to apply a positive voltage to one of the first and second capture beds, and a negative voltage to the other of the first and second capture beds. 
     
     
         85 . The system of any one of  claims 81  to  84 , wherein the separation vessel comprises a stack comprising a plurality of capture beds. 
     
     
         86 . The system of  claim 85 , wherein the plurality of capture beds are separated from each other by one or more separators. 
     
     
         87 . The system of  claim 86 , wherein the plurality of capture beds are in electrical contact with the first or second electrode. 
     
     
         88 . The system of  claim 87 , wherein the power source is configured to apply a positive voltage to the first electrode, wherein the first electrode is in electrical contact with a first plurality of capture beds, and wherein the power source is configured to apply a negative voltage to the second electrode, wherein the second electrode is in electrical contact with a second plurality of capture beds. 
     
     
         89 . The system of  claim 88 , wherein the first plurality of capture beds are stacked in an alternating fashion with the second plurality of capture beds. 
     
     
         90 . The system of any one of  claims 60  to  89 , wherein the ionic contaminant comprises an organic end with an ionic moiety. 
     
     
         91 . The system of any one of  claims 60  to  89 , wherein the ionic contaminant is selected from the group consisting of a polyfluoroalkyl ion, a borate, a phosphate, a polyphosphate, a sulfate, an organic acid, a fatty acid, a humic substance, a shortchain PFAS, a water-soluble medication, a detergent, a water-soluble insecticide, a water-soluble fungicide, a water-soluble germicide, and any combination thereof. 
     
     
         92 . The method of any one of  claims 60  to  91 , wherein the capture bed is at least partially conductive. 
     
     
         93 . The method of  claim 92 , wherein the capture bed is an activated carbon bed. 
     
     
         94 . The method of  claim 92 , wherein the capture bed is an ion exchange resin bed. 
     
     
         95 . The system of any one of  claims 60  to  93 , wherein the capture bed comprises powder, granules, beads, pellets, cloths, felts, nonwoven fabrics, or composites comprising a material selected from carbon, nitrogen-doped carbon, boron-doped carbon, charcoal, graphite, biochar, coke, carbon black, or any combination thereof. 
     
     
         96 . The system of  claim 95 , wherein the capture bed comprises activated charcoal. 
     
     
         97 . The system of any one of  claims 60  to  93 , wherein the capture bed comprises activated carbon having an average surface area of from about 100 m 2 /g to about 2000 m 2 /g. 
     
     
         98 . The system of any one of  claims 60  to  97 , wherein the capture bed has a conductivity of from about 0.01 S/cm to about 100 S/cm. 
     
     
         99 . The system of any one of  claims 60  to  98 , wherein the capture bed is surface-modified with functional groups selected from the group consisting of an acid, a hydroxide, a chloride, a bromide, a fluoride, an ether, an epoxide, a quinone, a ketone, an aldehyde, a pyrrole, a thiophene, and any combination thereof. 
     
     
         100 . The system of any one of  claims 60  to  99 , wherein the capture bed has a porosity of from about 30% to about 95%. 
     
     
         101 . The system of any one of  claims 60  to  100 , wherein the capture bed further comprises a binder dispersed in the capture bed. 
     
     
         102 . The system of  claim 101 , wherein the binder comprises a wax, a starch, a sugar, a polysaccharide, or any combination thereof. 
     
     
         103 . The system of any one of  claims 60  to  102 , wherein the separator comprises a porous plastic. 
     
     
         104 . The system of any one of  claims 60  to  103 , wherein the separation vessel is a pipe, column, or tank. 
     
     
         105 . The system of any one of  claims 60  to  104 , wherein the electrode comprises graphite, titanium, stainless steel, cast iron, a conductive metal oxide, a conductive diamond, a titanium suboxide, titanium nitride, titanium carbide, titanium boride, a doped manganese oxide, or mixtures or composites thereof. 
     
     
         106 . The system of any one of  claims 60  to  105 , wherein the aqueous wash liquid further comprises an antifreeze agent that lowers the freezing point of the aqueous wash liquid. 
     
     
         107 . The system of  claim 106 , wherein the antifreeze agent is selected from the group consisting of propylene glycol, polypropylene glycol, polyethylene glycol, glycerol, polyvinyl alcohol, carboxymethylcellulose, ribose, sucrose, glucose, rhamnose, xylose, fructose, raffinose, stachyose, low molecular weight hydroxyethyl starches, maltodextrin, cellodextrins, and any mixture thereof. 
     
     
         108 . The system of  claim 106  or  107 , wherein the aqueous wash liquid comprises from about 0.1 wt % to about 20 wt % of the antifreeze agent. 
     
     
         109 . The system of any one of  claims 106  to  108 , wherein the freezing point of the aqueous wash liquid is below about −0.3° C. 
     
     
         110 . The system of any one of  claims 60  to  109 , wherein the aqueous wash liquid further comprises one or more additives selected from the group consisting of acetic acid, propanoic acid, octanoic acid, glycolic acid, citric acid, ethylenediaminetetraacetic acid (EDTA), a water-soluble fatty acid, a salt of the aforementioned acids, and any mixture thereof. 
     
     
         111 . The system of  claim 110 , wherein the concentration of the one or more additives in the aqueous wash liquid is from about 0.1 wt % to about 15 wt % by weight of the aqueous wash liquid. 
     
     
         112 . The system of any one of  claims 60  to  111 , further comprising a rinse liquid line fluidly coupled to the vessel and configured to introduce a flow of aqueous rinse liquid to the vessel wherein the rinse liquid comprises one or more additives selected from the group consisting of acetic acid, propanoic acid, octanoic acid, glycolic acid, citric acid, ethylenediaminetetraacetic acid (EDTA), a water-soluble fatty acid, a salt of the aforementioned acids, and any mixture thereof. 
     
     
         113 . The system of  claim 112 , wherein the concentration of the one or more additives in the rinse liquid is from about 0.1 wt % to about 15 wt % by weight of the rinse liquid. 
     
     
         114 . A method of regenerating a capture bed comprising providing a vessel that houses a capture bed having one or more ionic contaminants bound to the capture bed, and flowing an aqueous wash liquid through the vessel. 
     
     
         115 . The method of  claim 114 , further comprising applying a voltage to an electrode in electrical contact with the capture bed, such that the one or more ionic contaminants bound to the capture bed is released from the capture bed and is washed from the capture bed via the aqueous wash liquid. 
     
     
         116 . The method of  claim 114  or  115 , wherein the aqueous wash liquid comprises a counter ion that binds to the ionic contaminant forming an aggregate contaminant phase that separates from the aqueous wash liquid. 
     
     
         117 . The method of  claim 116 , further comprising removing the aggregate contaminant phase from the aqueous wash liquid. 
     
     
         118 . The method of  claim 116  or  117 , wherein the aggregate contaminant phase separates from the aqueous wash liquid by precipitation. 
     
     
         119 . The method of  claim 118 , further comprising modulating the pH of the aqueous wash liquid to cause the aggregate contaminant phase to precipitate from the aqueous wash liquid. 
     
     
         120 . The method of  claim 114  or  115 , further comprising contacting the released ionic contaminant in the aqueous wash liquid with a stationary ion source, such that the ionic contaminant is bound to the stationary ion source and is thereby removed from the aqueous wash liquid. 
     
     
         121 . A system for regenerating a capture bed comprising:
 an electrode in electrical contact with a capture bed housed within a separation vessel;   a power source electrically coupled to, and configured to apply a voltage to the electrode;   a controller configured to control and modulate the voltage applied from the power source to the electrode;   a regeneration line fluidly coupled to the separation vessel and configured to introduce a flow of aqueous wash liquid to the separation vessel to wash ionic contaminant from the capture bed.   
     
     
         122 . The system of  claim 121 , wherein the aqueous wash liquid comprises a counter ion that binds to the one or more ionic contaminants thereby forming an aggregate contaminant phase that is substantially insoluble in the aqueous wash liquid. 
     
     
         123 . The system of  claim 122 , further comprising a filter configured to remove the aggregate contaminant phase from the aqueous wash liquid. 
     
     
         124 . The system of  claim 123 , further comprising a regeneration vessel that houses a stationary ion source configured to bind the one or more ionic contaminants in the aqueous wash liquid, wherein the regeneration vessel is fluidly coupled to the separation vessel.